A fixing device is known in which, as a result of a recording medium passing through a nip formed by two rollers, a toner carried on the recording medium is melted and pressed, and an image is fixed onto the recording medium.
In such a type of a fixing device, in order to surely prevent a recording medium having passed through a nip from being wound on a roller, such a configuration is known that a separation member having a separation claw or a separation plate is disposed near an exit of a nip, to strip off a leading end of a recording medium from a fixing member (for example, see Patent Documents Nos. 1 and 2, for example).
In an image forming apparatus that uses a toner for forming a visible image, a fixing device is installed for permanently fixing a toner image onto a recording medium such as a transfer sheet or the like.
In the fixing device, a recording medium passes through a pressing device (a fixing nip) that is formed by a fixing roller or a fixing belt heated and rotated, a pressing roller or a pressing belt pressed onto the fixing roller or the fixing belt and rotated, and so forth. As a result, a toner carried on the recording medium is melted and a toner image is fixed onto the recording medium.
In this regard, a sheet separation device including a separation claw or a separation plate is installed near the fixing roller or the fixing belt. The recording medium that would be wound on the fixing roller or the fixing belt with the melted toner is forcibly separated by the sheet separation device.
In this regard, when the recording medium is forcibly separated from the fixing roller or the fixing belt, the toner image on the recording medium comes into contact with a conveyance surface of the separation claw or the separation plate. As a result, a streaked image may be generated or a conveyance resistance for the recording medium may increase.
In order to avoid generation of a streaked image, Patent Document No. 3 proposes that respective shapes of a conveyance surface of a separation claw at an end and at a center with respect to a width direction of the conveyance surface are different from one another. That is, the end projects from the conveyance surface and the center is recessed from the conveyance surface.